FAQ

FAQ

Does TTSNative work offline?

Yes, once setup has finished. The first run needs internet access to download uv, Python 3.12, the server's packages and the Kokoro voice model. Installing the optional Chatterbox Turbo engine needs one more download. After that, reading, listening, voice creation and export all work offline.

Do I need a GPU?

No. Kokoro, the default engine, runs on the CPU only and uses about 1 GB of RAM while speaking. On the machine used for the performance measurements it generated speech about five times faster than real time. Older or low-power CPUs may not keep up with continuous playback at high speeds.

A GPU is only recommended for voice cloning: Chatterbox Turbo works best with an NVIDIA GPU (4 GB+ VRAM) or Apple Silicon, and is slower than real time on a CPU.

Where are my documents, recordings and audio stored?

In the data/ folder inside the project, unless you set LTTS_DATA_DIR. Settings → Storage shows the exact path and how much space each part uses. See Installation.

Does anything leave my computer?

No documents, recordings or generated audio. There are no accounts, analytics or telemetry. The only network requests are the downloads you start (setup and optional engines), from pinned sources with checksums. See Privacy and Security.

Which operating systems and browsers are supported?

Platform	Status
Windows 11	Fully tested: setup, unit and integration tests, real inference, and browser tests
macOS, Linux	Automated tests run in CI on macOS 15 and Ubuntu 24.04; the full app hasn't been tested by hand on them
Chrome, Edge, Firefox	End-to-end tested
Safari	Tested with Playwright's WebKit build on Windows; not verified on real Apple hardware
Phones	Layout and playback tested with Pixel 7 and iPhone 13 emulation; see Other Devices

Why is voice cloning optional?

Chatterbox Turbo is a large download (several gigabytes) and works best with a GPU. Its pinned dependencies also conflict with Kokoro's (it needs NumPy below 2, Kokoro's runtime needs NumPy 2 or newer), so it has to run in its own isolated environment. Keeping it optional means the basic reader never needs a GPU or a multi-gigabyte download. You install it from Settings → Engines & models only if you want it.

Can I clone a voice in a language other than English?

Not yet. In this app, Chatterbox Turbo is an English engine. Multilingual voice cloning is on the roadmap.

Can it read scanned PDFs?

Not yet: OCR isn't supported, so PDFs that are only images of text are refused, and image-only pages in other PDFs are skipped with a warning. Optional OCR is on the roadmap. See Reading Documents.

Does it highlight each word as it's spoken?

It highlights the whole sentence being spoken. Each sentence is its own audio clip, so the highlight is always in sync. Word-level highlighting from real model timings is on the roadmap.

Can I make audiobooks?

Yes. Export a document as an M4B audiobook with chapters, title, author, narrator and cover, as a read-along EPUB, or as MP3 or WAV (one file or a ZIP with one file per chapter and a playlist). Long exports pause, resume and survive a restart. See Exporting Audio.

What licences apply?

Component	Licence
TTSNative	MIT
Kokoro-82M model weights	Apache-2.0; training data includes CC BY material (Koniwa CC BY 3.0, SIWIS CC BY 4.0)
kokoro-onnx (ONNX export and runtime library)	MIT
Chatterbox Turbo (optional)	MIT, code and weights
espeak-ng (phonemisation, installed as a dependency)	GPL-3.0

Other dependencies have their own licences; see the licence inventory.

Can I use it on my phone?

Yes, on the same trusted Wi-Fi network: turn on LAN mode in Settings → Phones and tablets and pair the phone with the code shown there. Recording isn't available over plain HTTP, but you can import a recording. See Other Devices.